An apparatus detecting driving incapability state of a driver includes: a head detection portion that detects a head of the driver based on an image of a driver's seat captured by an imaging device mounted on a vehicle; and a shake detection portion that detects the driver is incapable of driving when an amplitude of a shake of the head detected by the head detection portion is smaller than a first amplitude or larger than a second amplitude, which is larger than the first amplitude, before a shake determination time elapses after external force has been applied to the vehicle during travel of the vehicle.